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V8 bargain (possibly)
NigeEss - 2/1/11 at 10:56 AM

NTDWM

V8 5.7L HEMI Engine - Never been run!! on eBay (end time 08-Jan-11 18:46:24 GMT)

mangogrooveworkshop - 2/1/11 at 11:45 AM

LEXUS LS 400 V8 ENGINE on eBay (end time 08-Jan-11 09:29:46 GMT)

Danozeman - 2/1/11 at 11:52 AM

What ecu could you use to make the 4 cylinders shut down apart from the standard one?

BenB - 2/1/11 at 12:09 PM

quote:
Originally posted by Danozeman

What ecu could you use to make the 4 cylinders shut down apart from the standard one?


Two 4-cylinder ECUs and a big switch

paulf - 2/1/11 at 12:49 PM

I would rather keep all 8 running but maybe you could use the staged injection option in megasquirt, or does the original system stop the valves from opening?
Paul

quote:
Originally posted by Danozeman
What ecu could you use to make the 4 cylinders shut down apart from the standard one?

ChrisW - 2/1/11 at 01:01 PM

quote:
Originally posted by paulf
I would rather keep all 8 running but maybe you could use the staged injection option in megasquirt, or does the original system stop the valves from opening?
Paul
quote:
Originally posted by Danozeman
What ecu could you use to make the 4 cylinders shut down apart from the standard one?


Strangely enough, Conrod and I were talking about this exact thing the other night.

I'd assumed there was a clutch type arrangement in the middle to 'disconnect' the front 4 cylinders. However, further thinking on this suggested that wasn't the best idea as the two 'halves' would get out of sync with the cams.

So we figured it must have some way of holding the valves open, presumably by a hydraulic actuator of some kind.

So, to run it on a Megasquirt, I'd be fitting a relay to the live feed to the second set of cylinders and to the hydraulic actuator then running it off the nitrous output on the MS. You can then set MS to fire that output when the load site is in a particular range.

No idea if that would work, but it's a starting point at least.

Chris

DRC INDY 7 - 2/1/11 at 01:27 PM

All it does is cut the fuel and spark to the cylinders it can also run with no coolant if it was all lost random cylinder firing displayed the heat

Danozeman - 2/1/11 at 01:49 PM

quote:

does the original system stop the valves from opening?


It cant stop them opening or youd lock the engine up. It must open the valves upto stop the drag from the 4 cylinder.

paulf - 2/1/11 at 02:07 PM

I was under the impression that some engines keep the inlet and exhaust valves closed hydraulically and the pressure balances out between the compression and exhaust strokes, surely if there kept open then it would blow back through the inlet manifold? .
Paul

quote:
Originally posted by Danozeman
quote:

does the original system stop the valves from opening?


It cant stop them opening or youd lock the engine up. It must open the valves upto stop the drag from the 4 cylinder.

PAUL FISHER - 2/1/11 at 04:39 PM

The Hemi engines are very heavy, cast iron blocks, the LS range of engines are much better for kit cars, like the Rover v8's they are all alloy blocks and heads.

ChrisW - 2/1/11 at 05:42 PM

That *is* an LS, isn't it?

Chris

PAUL FISHER - 2/1/11 at 09:43 PM

quote:
Originally posted by ChrisW
That *is* an LS, isn't it?

Chris


No Chris thats a Hemi for sale in the add, just happens to be the same displacement as the LS1 , Hemi is a Chrysler engine, the LS engine is a General Motors engine.

coyoteboy - 12/1/11 at 12:35 AM

quote:
It cant stop them opening or youd lock the engine up. It must open the valves upto stop the drag from the 4 cylinder.


No, I don't think so - you'd want to operate it as normal - the lowest restriction for the engine is operating it as normal - if they remained open full time you'd be pumping on all strokes, in the case of normal operation you're pumping on 2 strokes and using an air-spring to store and return energy on the other two. If you closed them all the time it'd be even better, efficiency-wise.